IRPC Annual Report 2023

Notes: (1) Thaioil Marine Co., Ltd. (TOM) has changed its name to Truth Maritime Co., Ltd. (TM) and is no longer a related company of the group of companies as of April 30, 2021. (2) Top Solvent Co., Ltd. (TS) has changed its name to Topnext International Co., Ltd. (TX) as of October 3, 2022. (3) Ubon Bio Ethanol Public Company Limited (UBE) is no longer a related company within the group of companies as of September 27, 2021. (4) PTT Energy Solutions Co., Ltd. (PTTES) has registered the dissolution of the company on December 29, 2022. (5) Dhipaya Insurance Plc. (TIP) is no longer a related company of the group of companies as of August 31, 2021. (6) GC Styrenics Co., Ltd. (GCS) registered to dissolve the company on August 31, 2022. Connected Transaction Policy and Requirements Significant connected transactions must be considered and approved by IRPC Board of Directors. As IRPC and its subsidiaries operate fully integrated petrochemical and refining businesses, the same business sector as PTT Group companies, connected transactions among IRPC, its subsidiaries, and PTT affiliates are inevitable and regarded as normal business activities. All such connected transactions, including trading in oil products and related services, as well as other transactions in support of normal business, are conducted on an arm’s length basis and which does not lead to benefit transfer among them. IRPC exercises due care in considering connected transactions based on reasonableness and to the best interests of the company. Measures Relating to Connected Transactions IRPC complies with the requirements of the SEC Office and the SET regarding connected transactions. The Board has duly examined transactions with potential conflicts of interest to ensure that they are conducted in a fair, transparent, and reasonable manner. Should a conflict of interest arise, the director, employee or any related party must recuse themselves from any discussion or voting on the issue in which they have a personal interest. In addition, on a quarterly basis, the Audit Committee reviews IRPC and its subsidiaries’ connected transactions with related companies or parties to avoid conflicts of interest and ensure IRPC’s best interest. Policy on Future Connected Transactions IRPC’s future connected transactions will be considered normal business transactions. The company will take into consideration the suitability of conditions and fair market prices. This is to ensure the best interests of all shareholders and stakeholders, in strict compliance with the corporate governance policy as well as SEC Office and SET’s regulations regarding connected transactions. Opinion of the Audit Committee Having reviewed all connected transactions, the Audit Committee was of the opinion that these connected transactions were conducted in the course of normal business activities, with reasonableness in terms of pricing suitably linked to market prices, and were conducted on an arm’s length basis, in conformity to the corporate governance policy and SEC Office and SET’s regulatory requirements. No. Company name and relationship Transaction (Unit: Million Baht) Characteristics and conditions 2023 2022 2021 34. PTT International Trading London Ltd. (PTTTLDN) Relationship: PTT Public Company Limited holds 100% of shares. - Purchase of goods - Other receivables (28) 28 (35) - - - IRPC received a share of compensation in the form of administrative fee for the purchase and sale of crude oil and products within PTT Group. 35. PTT International Trading Inc. (PTTTUSA) Relationship: PTT Public Company Limited holds 100% of shares. - Purchase of goods - Other receivables (1) 2 - - - - IRPC received a share of compensation in the form of administrative fee for the purchase and sale of crude oil and products within PTT Group. 36. PTT Treasury Center Co., Ltd. (PTTTCC) Relationship: PTT Public Company Limited holds 99.99% of shares. - Interest payables - long-term loan 1 31 1 31 - 31 IRPC subsidiary paid interest on PTTTCC loans. IRPC subsidiary borrowed money from PTTTCC. 277 Internal Control and Connected Transactions 56-1 ONE REPORT 2023

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